Windows 10 Redstone: A guide to the Insider Preview builds

Microsoft never sleeps. Even before the Windows 10 May 2019 Update (version 1903) started to roll out, the company began working on upcoming feature updates to Windows 10. As it did with version 1903, Microsoft has been releasing a series of public preview builds to members of Microsoft’s Windows Insider Program.

After years of using “Redstone” in its code names, Microsoft switched to a new format with the May 2019 Update. The new code names use a YYH1/YYH2 format, with the YY standing for the last two numbers of the year and H1 or H2 referring to the first or second half of the year. So Windows 10 version 1903, which was released in May 2019, was code-named “19H1” (for first half of 2019) rather than “Redstone 6.” The next feature update, due in the fall of this year, is code-named “19H2,” and the feature update that’s coming in the spring of 2020 is code-named 20H1.

To complicate matters, Microsoft earlier this year began releasing a number of early builds for Windows 10 20H1  before it released any 19H2 builds, first to its “Skip Ahead” Insiders, and subsequently to Insiders in the Fast ring. Then in July it began releasing 19H2 previews to Insiders in the Slow ring. From what we can tell, the company will continue to release 19H2 builds to the Slow ring and 20H1 builds to the Fast ring. (See “How to choose the right Windows 10 release channel” for an explanation of the rings and other Insider release options.)  

What follows is a list of every preview build of Windows 10 19H2 and 20H1 that has been rolled out to Windows Insiders, starting with the most recent. For each build, we’ve included the date of its release, which ring it was released to, a summary of what’s in the build and a link to Microsoft’s announcement about it.

After that you’ll find summaries of all the preview builds that led up to prior feature updates, from the Windows 10 May 2019 Update (version 1903, code-named 19H1) on back to the Windows 10 Creators Update (version 1703, code-named Redstone 2).

Note: If you’re looking…